I have an older project that is still using juce 3 that I haven’t had time to upgrade yet. I’m seeing the following error:

2016-11-16 07:52:57.488455 Plugin Host[1477:50003] dynamic_cast error 1: Both of the following type_infos should have public visibility. At least one of them is hidden. N4juce8TypefaceE, N4juce11OSXTypefaceE.
2016-11-16 07:53:34.784768 Plugin Host[1477:50003] dynamic_cast error 2: One or more of the following type_infos has hidden visibility. They should all have public visibility. N4juce9ComponentE, N4juce9PopupMenu13HelperClasses10MenuWindowE, N4juce15ResizableWindowE.

2017-01-31 02:00:31.348396 Plugin Host[23257:7776575] dynamic_cast error 1: Both of the following type_info's should have public visibility. At least one of them is hidden. N4juce8TypefaceE, N4juce11OSXTypefaceE.
2017-01-31 02:00:31.349850 Plugin Host[23257:7776575] dynamic_cast error 1: Both of the following type_info's should have public visibility. At least one of them is hidden. N4juce8TypefaceE, N4juce11OSXTypefaceE.
2017-01-31 02:00:31.350219 Plugin Host[23257:7776575] dynamic_cast error 1: Both of the following type_info's should have public visibility. At least one of them is hidden. N4juce8TypefaceE, N4juce11OSXTypefaceE.

This usually comes up when a plug-in throws some kind of Obj-C or C++ exception. I don’t think it’s actually related to OSX type faces. But I’m not entirely sure. Are you seeing this during scanning or plug-in instantiation/deletion?